Decolorizing oil



NOV. 18, 1941. w A, PRQELL 2,263,102

' DEcoLoRIzING OIL Filed Dec. 15, 1939 Clay uwled auf/1 40% fol/0%@ zuel/'pl of' 60% o .9.5% swan-c and llniwazzed Q@ Patented Nov. 18, 1941 DECOLOEIZING OIL Wayne A. Proell, Chicago, Ill., assigner to Standard Oil Company, Chicago, Ill., a corporation of Indiana Application December l5, 1939, Serial No. 30S-,403

Claims.

This invention relates to improvements in the decolorization of oils and more particularly to improvements in the decolorization of petroleum oils by clay percolation.

In the preparation of finished petroleum oils the petroleum distillate after preliminary treatment with sulfuric acid and/or solvent extraction is percolated through a bed of decolcrizing material such as diatomaceous earth,fuller's earth and the like to obtain a final product having the desired color.

I have discovered that greatly improved efficiency and filter yields can be obtained by mix ing the filtering clay with from about 40% to about 110% by weight of a mineral acid based on the weight of clay used prior to filtering the oil through the clay, '.fhe amount of acid used should not be greater than that required to form a free flowing solid mixture when mixed with the clay. The upper limit of the amount of acid used is the maximum amount which can be mixed with the clay without changing the clay-acid mixture from a free-flowing non-sticky granular mass to a sticky mass or a liquid slurry. For ex ample, using a typical clay-No. 1 bunt Attapulgus claythe upper limit of added 95% sulfuric acid is about 110% of vthe weight of the clay. The acid may be concentrated or dilute sulfuric acid. sludge acid obtained from the acid sludge iesulting from the treatment of petroleum oil with sulfuric acid, phosphoric acid. or hydrochloric acid. I prefer to use, however, miluric acid of from about 60% to about 95% concentration. or sludge acid.

The term "acid-wetted clay used herein and in the appended claims means a mixture of acid and clay, in which the mixture contains insufficient acid to render it sticky or liquid.

The accompanying drawing illustrates. by way of example, a filtration bed having three layers of filtering clay according to the invention.

1n preparing the filtration bed I prefer to first place in the bottom of the percolator I s. layer 2, comprising up to about '7% of tie total depth of the nltration bed. of clay which has not been wetted" with acid, and then superimrose upon the bottom layer of clay 2 a layer of clay 3 which has been wetted with from about 40% to about 110% of its weight of acid. The tlltration bed is then finished on by a top layer 4 oi acid wetted clay in which the acid content is much css than the middle layer of acid wetted clay: preferably the top layer 4 is a clay wetted with between about 5% and about 40% by weight of the clay used of acid, The percolator l has conventional ir..et pipe 5 and outlet pipe 6. The above arrangement of clays is preferred since it minimizes the clogging of the clay column by precipitated color forming bodies and/or asphalts contained in the oil. These materials precipitate slowly and uniformly in the uppermost acid-poor clay layer l, and rapidly in the middle acid-rich clay layer 3. Since the oil is substantially clean by the time it reaches the middle clay layer 3 it does not clog this clay stratum, and the rate of filtration is not materially atlected.

While the foregoing arrangement of the filtration bed is preferred, particularly when oils having a high content of color forming bodies are being percolated, 1 may dispense with the top layer of acid-poor clay 4 if the oil to be filtered does not have a high content of color forming bodies.

The effectiveness of my improved method is illustrated by the following exampes which are exemplary of the invention and not intended to be a limitation thereof.

Example 1 Two parts of Attapulgus clay were mixed with about one part of sulfuric acid to produce a product which was a free flowing granular mixture. A layer of untreated Attapulgus clay was placed in the bottom of a percolation tube and about one-half as much of the treated clay then placed on top o1 the untreated clay. A Diesel fuel of 8 N. P, A. color was then percclated through the column to produce a nished oil having a color of about 3 to 3*/2 N. l`. A., with a yield equivalent to about 10,000 gallons of oil per tor. of clay. y

Example 2 One part of Attapulgus clay was mixed with about one and one-half parts of concentrated sulfuric acid, one part of the oil to be filtered. and about three parts of sea sand. The latter material was incorporated to increase the porositv o1' the mixture. A layer of untreated clay was placed in a percolation tube and about an equal amount of the clay-acid-sand mixture placed on iop of the untreated clay. An untreated oil of B N. P, A. color was percolaied through the tube, and an oil having a color of 1% to 2- N. P. A.. with a yield of about 10,000 gallons of oil per ton of clay was obtained.

Filtering the same oils through untreated clay alone to a yield of about 10.000 gallons of oil per ton or clay, a percolated oil having a 'I N. P. A. color was obtained. Acid treating the ancianos that ,8i .volf'lf humain@ decolorizing emciency of the spent clay was greatly enhanced simply by acid-wetting the same.

While I have described certain preferred ex amples of my invention and the manner o! carrying out the same, I do not intend to limit myself thereto, since the precise proportions oi the materials utilized may be varied without departing op .une Q .prof them ed in the 102:; i, c a

1. The method ol decoloriz-.ing e petroleum oii comprising wetting a decolorizinr, 'lay with from f-"l '-'fli Test Treatment (Nglf.)

1V-@fle q1' antw i .A A, on nfs N. P. A. color mma vinti-015% mso.;

filtered at once through paper, and then clayed (untreated clay)M444 T 4% li. Same as A, except acid-trehtd oillwaspiny mitted to settle 60 minutes before liltrntion and clay percolation r :i1/5 C Some es A, except acid-treated oil permitted to settle i8 hours beiore filtration and clay percolntion.VV 2l/5 i)Y -OlLoi' 8 N. P.- A eolor- (not aeidftreetedl per colated through acid-wetted clay 1i-2-2 (In the above'tests all oils were percolated to give yields of 10,000 gallons off'oil pei" ton of clay). The data show` vthe enhanced eiliciency obtained when percolati'ng With'a'cidrwetted clays,

' Althoughjmyinvention is' applicable to the clay percolation' of any ou, it is particularly adaptable to, and most efficient for the clay percolation oi oils rich. in asphaltenes and'in which improvement in color is effected by the' 4removal of such asphaltenes. i 4 i Aiurther advantage obtained' with; my invention is the revivifv'ing 'effect obtained when applying the invention to' spentvclaysf. Clays which have been used for the percolation of oils which apparently have no further decolorizing eiect upon the oil being treated, when acid' wetted in accordance with my invention are again able to remove coloring 'matter from: oils percolated therethrough without the necessity of burning and/or otherwise revivifying the clay. Thus an oil was percoiated through clay until the nitrate hada color of about 8 N. P Am indicating that thedecolorizing power ofthe clay vjas exhausted. The 'exhausted clay was then'w'etted with concentrated sulfuric acid, in themanner described above. and oil again percolated through the acidwetted exhausted clay. A nitrate was obtained having a color of 3 N. P. A. with a yield of 10,000 gallons of oil per ton of clay. indicating that the ."el5o'ifiil0% to about 110% by weight of sulfuric acid Togli; nix agbo, trl% to about 95% strength anglpeigdaatin ,le minerai oil through a bed f the acidgyigeiftfed decolorizing clay.

2. The method ot removing color forming *bodies fromm-*petroleum oil containing the same comprising weting a decolorizing clay with from about '40% to about 110% hy weight of sulfuric acid orrromvabout 60% toaboutewsirehgth. superimposing a vsubstantial i layer 'oil thel acidwetted clay uponfa layer of uhtreated'decolorizing clay and percolating the mineral oil through seid clays. f

3. In the deeolorizatio'n of minerai oils by percolation through iullers earth the improvementcom'prisingtirstwetting said Iullers earth with from about `40% to about 110% by weight of sulfuric acid of. from about 60%1 to about 95% strength. and subsequently percolting theV mineguil through said sulfuriclaeid-wetted'fuller's e f 4. The method of removing color forming bodies from a. petroleum oilr containing -thesame comprising percoiating the oil ,throughy a .filtration bed comprising a lowermost layer of ya decolorizing clay which has not been, acid-wetted, a middlelayer of clay wetted with fromY about 40% toabout 110% of e sulfuric acid based on the weight oi' the clay used. and a top layer of clay wetted withtroxn about' 5% to about 40% of a sulfuric acid based onthe weight of the clay used, the sulfuric acid in each case having a strength of lfrom about 6.0% to about 5. In ai process for "removing color forming bodies from apetroleum oil the step comprising percolating the oiithrough abcd of clay wetted with from about 40% to about 110% by weight oi' sulfuric acid having a strength of fromfabout 60% to about 95%. t WAYNE A. PROELL. 

